Electric ignition device for gaseous fuel



Sept. 2, 1958 w. s. KUNZLER 2,850,084

ELECTRIC IGNITION DEVICE FOR GASEOUS FUEL Filed March 19, 1954 3Sheets-Sheet 1 INVENTOR. Widlzanz S K561227631".

HTFORZVZ'Y ELECTRIC IGNITION DEVICE FOR GASEOUS FUEL Filed March 19,1954 Sept. 2, 1958 w. s. KUNZLER 3 Sheets-Sheet v2 I INVENTOYR. Wildcanz5f li izlzzlen HIS HTTORNEY p 2, 195,8 w. s. KUNZLER I 2,850,084

ELECTRIC IGNITION DEVICE FOR GASEOUS FUEL Filed March 19, 1954 3Sheets-Sheet 5 INVENTOR. VVcllamz 6T Kazzzlen ELECTRIC IGNITION DEVICEFOR- GASEOUS FUEL Application March 19, 1954, Serial No. 417,466

4 Claims. (Cl. 158-115) This invention relates to electric ignitiondevices for gaseous fuel burners and, more particularly, to electricresistance igniters.

The wire material of which electric resistance igniters are made may becatalytic or noncat-alytic. An example of the former is platinum-iridiumalloy which displays a high minimum life and uniform ignitionperformance from day to day as well as ability to ignite a wide varietyof gas-air mixtures when the wire is brought to suitable temperature.Combustion occurs on the surface of this metal catalytically with theevolution of gases which exert a quenching efiect tending to preventignition. This accounts for the relatively high ignition temperaturesrequired with catalytic metals in general.

Resistance coils brought to incandescence by the passage of electriccurrent therethrough have been used ,extensively to ignite flowingcombustible fuels such as gas-air mixtures. Such igniters have beensupported in housings of various types for protecting the coil andfacilitating ignition. In addition, resistance coils of variousconfiguration are employed to surmount numerous difiiculties found inelectric ignition devices. A straight Wire igniter or a sine wave typeigniter would avoid the difficulty found in a helix type igniter, thatis, a concentration of evolved gases in the spaces between the coils.However, the former igniters would require a close current regulation toinsure proper igniter coil life. This is apparent from the length ofresistance wire used in such igniters since a particular quantity ofcurrentmust flow over a shorter length of wire and when ignition occurs,these igniters are subjected to a high temperature gradient over theirshort length, in the presence of the cooling effect of the flowinggas-air mixture on the small mass.

In either case, the use of a helical coil, a straight Wire or a sinewave type involved one corrimon difliculty differing only in degree anddepending upon the length of resistance wire utilized. The normaloperation of electric ignition systems depends upon the flowingofgas-air mixtures through a flash tube and thence to an igniter wireadjacent one end of the tube. As pointed out above, when the mixtureimpinges upon the wire, the combustion occurs on the wire and theignited mixture is flashed back through the tube. However, beforeignition, there is a cooling effect experienced by the igniter wire,caused by the relatively fast flow of mixture toward and around thewire. Heretofore, this cooling effect could only be overcome byelevating the temperature of the igniter at the instant of i nition byincreasing the normal flow of current in the igniter circuit.

Another disadvantage found in the present day use of electric ignitionsystems is the inaccessibility of the various parts which go to make upsuch a system. Heretofore, it was necessary to employ an experienced.serviceman to replace a spent igniter and this required the dismantlingof the range and the manipulation of several electrical and mechanicalconnections.

In apreferred embodiment of this invention, a baffle Patented Sept. 2,1958 2 means is provided for preventing a frontal flow of gas airmixture to an igniter coil, such means deflecting the flow of themixture toward openings provided in the shield, which openings then, inturn, allow the mixture tosurround the coil thus insuring completeimpingement of the mixture.

The igniter coil and its housing are constructed and arranged to beeasily plugged in a receptacle whereby instant removal of the coil andhousingcan be efiect ed without dismantling the range or oven. Tofacilitate this removal, the flash tube assembly is made to bedetachable from the oven wall by a mere manual twist of the'tube'.

It will be apparent from the foregoing brief description that one of theobjects of the invention is to facilitate the instant removal andservicing of ignition wires used'in electric ignition systems withoutthe burdensome dismantling of oven parts.

Another object of the invention is'to embody the igniter housing devicein a small compact unit having the operation-al feature of a plug-incoil.

Another object of theinventi'on is to control the flow 0f the gas-airmixture to the igniter coil thereby permitting the ignition of gas atlower coil temperatures.

Other objects and advantages will become apparent from the accompanyingspecification and claims in connection with the accompanying drawingswherein:

Fig. 1 is a plan view of the improved electric ignition device inposition near'a main burner and itsassociated pilot burner;

Fig. 2 is a cross section along line IIII in Fig. 1;

Fig. 3 is an elevational view taken along line III-III of Fig. 1; I V

Fig. 4 is a perspective view of the igniter housing unit and associatedparts;

Fig. 5 is an enlarged side elevation of the shield separated from thehousing;

Fig. ,6 is a cross section along line VI-VI of Fig. 5; and

Fig. 7 is a cross section along line VII'VII of Fig. 3.

Referring more particularly to the drawings, Fig. 1 thereof depicts aheating means for an oven comprising a main burner 10, an automaticpilot burner generally indicated at 12, a casing 14 supported on ovenwall 16,. having an elongated igniter housing assembly 18 ofsubstantially rectangular formation in plan detachably secured to thebottom wall 20 of casing 14.

Referring now more particularly to the ignition housing assembly 18, thearrangement comprises a support bracket 22 having integral therewith twoside substantially rectangular plates 24, 26, as shown in Fig. 2. Anigniter coil 28 has one end secured as by solder to one end of sideplate 26 while the other end of the igniter coil 28 is soldered to oneend of plug-in pin 30. Arranged longitudinally of housing assembly 18and adjacent plate 24, pin 30 projects through openings 32, 40in cup 34being insulated from cup 34 by means of mica washers 36 and a suitableceramic cement-filling 38 which secures the pin 30 to the supportbracket 22. Also secured to support bracket 22, as by riveting or othersuitable means, is-p'lugin pin 42.

At the outer end of support bracket 22, a U-shaped shield 44 having itsbottom portion 46 and bafiie plate 47 of semicircular cross-section,bridges the open end of chamber 48 formed by the parallel side plates24, 26- of bracket 22, and parallel, sides 50, '52 of'shield 44. Sides50, 52-have extending therefrom tongues 54 which are urged by theresiliency of sides 50, 52 into engagement with projections 56 on sideplates 24, 26, as shown in Fig. 1.

In assembling shield 44 to support bracket 22, the outer edges of :sides50, 52'engage theinclined surfaces. 5801 side plates 24, 26, and byapplying a slight manual force to shield 44, the sides 50, 52 willspring apart as the respective edges slide along inclined surfaces 58until tongues 54 have traveled beyond projections 56 and into slots 60.The bottom portion 46 ofthe U-shaped shield 44 is provided withelongated openings 62, 64 and with baffle plate 47 longitudinallydisposed therebetween substantially as shown in Figs. and 6 and whichwill be more fully described hereinafter.

The casing 14 has depending therefrom an overhanging rectangular frame66 overlying the edges adjacent opening 17 in wall 16 and supportingfour threaded screws 68 for securing the casing to the wall throughaligning openings in the frame and wall, as previously indicated. Thebottom wall of the casing is formed from mica sheets or any othersuitable insulation material having similar rigidity and has twoapertures 70, 72 formed therein for the reception of plug-in pins 30 and42 respectively. -It is to be noted here that plug-in pins 30, 42 areinsulated from the casing 14 as are pin sockets 74, 76 which areattached to the mica wall by rivet 78;

Also riveted to wall 20 and communicating with pin sockets 74, 76 bymeans of rivet 78 are terminal angle plates 80, 82 as shown in Fig. 2.Pin sockets 74, 76 may be formed from any suitable conducting materialand so shaped as to be adapted to resiliently retain the plug-in pins30, 42. The leads 84, 86 are connected to a suitable source ofelectrical energy, such as 115 volts house current, and the transformer88 will serve to step down this current to the requisite rated voltageof the ignition coil 28. The ignition device of this invention iscompleted by the provision of a pair of leads 90, 92, electricallyconmeeting the secondary of transformer 88 to terminal angle plates 80,82, respectively.

The flow of gas-air mixture from the pilot burner 12 is directed to theignition coil 28 by means of a flash tube 94, which may be of anydesired length depending upon the proximity of the pilot burner withrespect to the coil. The flash tube 94 is integral with 'a cover plate96 which is detachably secured to frame 66 of casing 1.4. Referring moreparticularly to Figs. 3 and 7, there is shown a curved slot 98 at eachend of cover plate 96, an enlarged aperture 100 at one end of each ofthe slots and a pin means 102 extending through the slots and aligningopenings 104, 106 formed in the frame 66 and oven wall 16 respectively.

A light coil spring 108 encircles each pin 102 and is retained undercompressionby lock washers 110 secured to the pins at the ends thereof.Having apertures 100 slightly larger than heads 114 of pins 102, thecover plate 96 is first positioned adjacent the oven Wall and casing ata slight angle than that shown in Fig. 3, so that apertures 100 willallow heads 114 to pass therebetween. Rotating the plate 96 causes theshank of the pins to follow the relatively narrow slots 98 therebyeffecting a slight compression of springs 108 due to the sliding motionof the inclined surfaces 112 on the edges of the slots. Since the heads114, at this point, are larger than the corresponding portion of theslots, the cover plate is resiliently held to both the oven wall and thecasing frame. This arrange ment for the cover plate offers a twist lockmeans for detachably securing the flash tube 94 to an oven wall andcasing and may be accomplished by the mere manual twisting of the flashtube.

In operation of the system, before ignition, a gas-air mixture isallowed to flow through the flash tube 94. The direct impingement of themixture upon the ignition coil is impeded by the baffle plate 47 ofshield 44 which plate operates as a deflecting baffle plate fordirecting the mixture to the openings 62, 64. Passing through theseopenings, the mixture impinges on the sides of the coiland because aslight pressure exists behind the baffle portion 47 adjacent the coilcaused by the rushing mixture passing through openings 62, 64, some ofthe mixture flowing through the opening is sucked back toward theunderside of the bafile plate and consequently impinges upon the frontportion of the coil. This arrangement and design of the shield 44, ineffect, slows down the flow of the mixture and allows the coil to beexposed to the mixture from all sides simultaneously. Upon ignition theignited gas flows back through the flash tube to light the pilot andmain burner as is well known in the art.

In the event of ignition coil failure, easy removal and replacement isfacilitated by the plug-in feature of the igniter housing. This functioncan be performed by a housewife or anyone not skilled in the intricateelectrical ignition system found in most everyday electrical appliancesof this type. in fact, the operation requires no more than is necessaryto replace a common household fuse. The operator need only twist theflash tube to disengage it from the wall of an oven, pull out the spentigniter coil, insert a new one, and replace the flash tube to itsoriginal position, all this without the cumbersome procedure of -movingthe entire appliance away from its adjoining wall,

dismantling the back of the oven, loosening and disassembling variousassociated electrical and mechanical connections, and then repeat thesesteps in the reverse order.

It will be understood that many changes may be made in the details ofconstruction and arrangement of parts without departing from the scopeof the invention so that this description and accompanying drawings areintended by way of illustration only and are not to be construed in alimiting sense.

I claim:

1. An electric ignition device for a flowing fuel comprising a housinghaving an enclosed chamber therein, a resistance wire carried by saidhousing within said chamber and having an igniter coil portion positionsin proximate relation to one wall of said housing, said igniter coilportion having a longitudinal axis, said wall having an elongatedopening positioned on either side of and spaced from said, igniter coilportion, each of the elongated openings having the major axis thereofsubstantially parallel to the longitudinal axis of said igniter coilportion for deflecting the flow of fuel away from said igniter coilportion upon passing through the openings, whereby a quenching effecttending to retard ignition due to the rapid cooling of said igniter coilportion caused by the flow of fuel is prevented.

2. In an electric ignition device for a flowing gas-air mixture, thecombination comprising a housing, said housing including a supportbracket, a first side plate projecting from one end of said supportbracket transversely to the plane thereof, a second side plateprojecting from the other end of said support bracket transversely tothe plane thereof and being in a spaced substantially parallelrelationship with said first side plate, a shield having spaced sidemembers secured to said side plates remote from said support bracket andhaving a medial portion cooperable with said housing for defining anenclosed chamber therein, an opening on each side member oppositelydisposed on either side of the medial portion of said shield foremitting fuel to said chamber, an insulated prong secured to saidsupport bracket and having a projection within said chamber, and anigniter coil positioned wholly between the openings in said shieldwithin said chamber in proximate relation to said wall and beingshielded from entering fuel by the medial portion of said shield, saidcoil having one end secured to said first side plate and the other endconnected to said projection.

3. An electric ignition device as defined in claim 2 wherein theopenings are elongated and are substantially equal in length to saidigniter coil.

4. In an electric ignition device for a flowing gas-air mixture, thecombination comprising a housing having an enclosed chamber therein, onewall of said housing having a surface arcuate in cross section andhaving opposed openings defining achord thereacross and a medial portiontherebetween, a resistance wire including an igniter coil positionedwithin said chamber in proximate relation to said one wall of saidhousing, said igniter coil having a longitudinal axis extendingsubstantially parallel with the surface and substantially perpendicularto said chord, of said wall, and a flash tube directed toward said oneWall for supplying fuel to said chamber through said openings, said onewall being adapted to have a bafiling effect on the fuel supplied bysaid flash tube for-directing the flow of fuel to said openings and awayfrom said coil whereby a quenching eflect tending to retard ignition dueto the rapid cooling of said coil caused by the flow of fuel isprevented.

References Cited in the file of this patent UNITED STATES PATENTSKellermann Nov. 15, Dester Apr. 3, Focke et a1 June 16, Ragan Sept. 22,Fox Sept. 25, Cohn Nov. 8, McDougal Aug. 18,

FOREIGN PATENTS Switzerland May 1,

